High free volume membrane for gas separation

Patent metadata

Field	Value
Publication number	US-12134068-B2
Application number	US-202318317652-A
Country	US
Kind code	B2
Filing date	May 15, 2023
Priority date	Jan 4, 2021
Publication date	Nov 5, 2024
Grant date	Nov 5, 2024

Abstract

A gas separation membrane, methods of forming the membrane, and methods of using the membrane for gas separation are provided. An exemplary gas separation membrane includes a cellulosic matrix and a polymer of intrinsic microporosity (PIM). The PIM includes chains coupled by a heat-treating under vacuum.

First claim

What is claimed is:

1. A method for forming a gas separation membrane, comprising:
forming a cellulosic polymer solution;
forming a polymer of intrinsic microporosity (PIM) solution;
blending the polymer solution of the cellulosic polymer with the polymer solution of the PIM to form a mixed polymer solution;
forming a dense film from the mixed polymer solution;
drying the dense film; and
heat-treating the dense film under heat and vacuum to couple the PIM chains.

2. The method of claim 1 , comprising dissolving a cellulosic polymer in tetrahydrofuran (THF) to form the cellulosic polymer solution.

3. The method of claim 1 , comprising forming the cellulosic polymer solution by dissolving cellulose acetate in THF.

4. The method of claim 1 , comprising dissolving the PIM in THF.

5. The method of claim 1 , comprising forming the PIM polymer solution by dissolving PIM-1 in THF.

6. The method of claim 1 , comprising dissolving an amount of the PIM that is in a weight ratio to the cellulosic polymer of between about 2.5 wt. % and about 40 wt. %.

7. The method of claim 1 , comprising dissolving an amount of the PIM that is in a weight ratio to the cellulosic polymer of between about 5 wt. % and about 20 wt. %.

8. The method of claim 1 , comprising forming triazine rings during the heat treatment under vacuum, wherein the triazine rings couple the PIM chains.

9. A method for removing an acid gas from a natural gas feedstock to form a sweetened natural gas, comprising:
flowing the natural gas feedstock over a membrane, wherein the membrane comprises:
a cellulosic matrix; and
a polymer of intrinsic microporosity (PIM), wherein the PIM comprises chains coupled by a heat-treating under vacuum; and

isolating the acid gas in a permeate from the membrane; and
producing the sweetened natural gas in a retentate from the membrane.

10. The method of claim 9 , comprising forming the cellulosic matrix from cellulose acetate (CA).

11. The method of claim 9 , comprising forming the PIM from PIM-1.

12. The method of claim 9 , wherein the PIM comprises triazine rings formed by the heat-treating under vacuum.

13. The method of claim 9 , comprising forming larger free volume spaces and smaller free volume spaces by the heat-treating under vacuum.

Assignees

• Saudi Arabian Oil Co

Inventors

• Yang Junyan

Classifications

• B01D67/00113

  Pretreatment of the casting solutions, e.g. thermal treatment or ageing · CPC title

• C10L2290/548

  Membrane- or permeation-treatment for separating fractions, components or impurities during preparation or upgrading of a fuel · CPC title

• C10L3/104

  Carbon dioxide · CPC title

• B01D2325/023

  Dense layer within the membrane · CPC title

• B01D71/62

  Polycondensates having nitrogen-containing heterocyclic rings in the main chain · CPC title